There is food processing apparatus of the type broadly set forth above called a food processor and having a working bowl or vessel with a motor-driven shaft projecting vertically upwards through the bottom of the bowl. Various selected rotary tools can be engaged on and driven by the shaft for performing many different food processing operations as may be desired by the user. A detachable cover is secured over the top of the bowl during use. This cover includes a hopper or feed tube which has a mouth that opens downwardly through the cover into the top of the bowl. The food items to be prepared may be placed in this feed tube and then are manually pushed down through the feed tube ino the bowl by means of a removable pusher member which is adapted to slide down into this feed tube in the manner of a plunger. For further information about this type of food preparing apparatus the reader may refer to U.S. Pat. No. 3,892,365 of Pierre Verdun and U.S. Pat. No. 3,985,304 of Carl G. Sontheimer.
The interchangeable rotary tools which may be used in a food processor include slicing discs, rasping discs, grating discs, etc. which have a disc-like cutting tool member formed of sheet metal, preferably stainless steel, with one or more cutting elements projecting above the upper surface of the cutting disc member. These tools which have a disc-like cutting member are intentionally positioned in the top of the bowl near the lower surface of the cover where they can cut, slice, rasp, or grate the food items entering downwardly from the feed tube into the top of the bowl. For the purpose of positioning the disc-like cutting tool member in the top of the bowl, such a rotary tool may include a relatively long hollow hub extending relatively far down into the bowl, depending upon the height of the motor-driven tool shaft in the bowl. This hollow hub slides vertically down around the upper end of the tool shaft. In order to provide a driving connection between the shaft and this hollow hub, the shaft is formed with driving coupling means, such as a flat face, keyway or spline, and the hollow hub has complementary coupling means, such as internal lugs, keys, or grooves for engaging the shaft. Thus, each of the various disc-like cutting tools can be engaged quickly and easily with the shaft in a positive driving relationship and also can be removed quickly and conveniently to be replaced by another.
One type of food preparation is the cutting of food material, such as a potato, into julienne strips. The cutting of a potato into such strips of small rectangular cross section requires that it be sliced in two perpendicular planes. The slicing disc of the prior art as shown in said Verdun and Sontheimer patents has a single, horizontal blade spaced above the plane of the disc and is well suited for slicing a potato into slices of uniform thickness. It would, of course, be possible to remove the potato slices from the working bowl and then manually to cut these slices into small strips by using a sharp knife, but this would defeat one of the major advantages of the food processor, which is to perform each desired preparation quickly and accurately in a short time cycle. For a number of years the food processor industry has been needing and lacking a strong, reliable, readily fabricated julienne cutter.